Japanese beetle adults are a major problem in landscapes because they feed on a wide variety of annuals, perennials, trees, shrubs, and vines. However, certain plants are more susceptible to their attack. These plants are listed in Table 1. In contrast, many plants are less susceptible to attack by Japanese beetle adults. These plants are listed in Table 2.
Research has demonstrated that natural sugar content and presence of odoriferous substances are important factors in determining the susceptibility of plants to attack by Japanese beetle adults. A study showed that plants with higher amounts of the reducing sugar dextrose suffered greater damage from beetle adults than plants with lower amounts of dextrose.
Table 1. Ornamental plants highly susceptible to feeding by Japanese beetle adults.
Table 2. Ornamental plants less susceptible to feeding by Japanese beetle adults.
|Japanese maple ||Norway maple|
|Gray birch ||Horsechestnut |
|Black walnut ||Sassafras |
|American elm ||Althea |
|London planetree ||Rose |
|Black cherry || Crab apple |
|American mountain ash ||Lombardy poplar |
|Pussy willow ||American linden |
|Red maple ||Silver maple|
|American holly ||Boxwood |
|Snowberry ||Winged euonymus |
|Flowering dogwood ||White cedar |
|Yellow poplar ||Saucer magnolia |
|White ash ||Green ash |
|Lilac ||Norway spruce |
|Scotch pine ||Douglas fir |
|Canadian hemlock ||Mock orange |
|Hydrangea ||Yew |
|Forsythia || |
Odoriferous chemicals have also been shown to play a role in the attractiveness of certain plants to Japanese beetles. Ginkgo biloba, which is not usually attacked by Japanese beetle adults, may lack certain odoriferous chemicals that are attractive to them. However, many susceptible plants such as rose and apple contain the substance geraniol, which is highly attractive to Japanese beetle adults. It should be noted that when Japanese beetle adult populations are heavy and food is a limiting factor, plants that are less susceptible to Japanese beetle adult feeding might be fed upon.